Improve Soil Nutrient Status Research Articles

Dairy effluent applications to a pasture enhance soil fertility and microbial activity without impacting soil bacterial and fungal community composition

Farm dairy effluents (FDE) from washing the milking parlor contain manure, urine, and chemicals and constitute a large amount of wastewater. Applying FDE as soil fertilizers to pastures can enhance forage yield and improve soil nutrient status. Since the dairy industry is increasingly attempting to maximize returns through better utilization of forage with lesser inputs, there is demand for a supply of FDE as fertilizers. Nevertheless, the impact of this practice on soil microbiota remains largely unexplored. It must be studied before large-scale soil disposal to avoid diminishing microbial diversity or enhancing pathogen abundance. This study evaluated the effects of applying lagoon-stored (Lagoon) and raw dairy effluents (Raw) at a rate of 50 kg N ha−1 in four equal doses, in comparison to urea fertilization, on soil fertility and the activity, abundance, and community structure of soil microbiota. Raw was obtained after solid separation, and Lagoon corresponds to the Raw stationed in a two-lagoon system. Microbial activity was assessed as basal respiration, potentially mineralizable N, potential nitrification activity, and enzymatic activities. The catabolic activity of the microbial community was evaluated using Biolog Ecoplates™. Bacterial and fungal community composition and diversity were analyzed through amplicon sequencing of 16S rRNA and ITS2. The application of FDE benefited soil fertility and microbial activity. Lagoon had the most potent effects on soil available P and extractable K+, Na+, Mg2+ and Ca2+. Soil treated with Raw displayed higher microbial activities, such as dehydrogenase, basal respiration, urease, and potentially mineralizable N, than the other treatments. FDE did not significantly alter the microbial composition, abundance, or functional diversity. In conclusion, in this short-term trial, despite changes in soil chemical properties and microbial activity, the composition and diversity of the bacterial and fungal communities remained unaffected by FDE irrigation.

Anaerobic soil disinfestation rather than Bacillus velezensis Y6 inoculant suppresses tomato bacterial wilt by improving soil quality and manipulating bacterial communities

Continuous cropping leads to high incidence of soilborne diseases such as bacterial wilt caused by Ralstonia solanacearum, which poses a risk to agricultural production. Anaerobic soil disinfestation (ASD) and plant growth-promoting rhizobacteria (PGPR) are considered environmentally friendly methods to control bacterial wilt. However, the underlying mechanism of the improvement of soil health and the inhibition of bacterial wilt after ASD treatment and PGPR inoculation needs further exploration. This study evaluated the effect of ASD treatment on soil improvement at pre-planting of tomato, and the effect of ASD treatment combined with the application of Bacillus velezensis Y6 (BV) on soil quality, R. solanacearum abundance, and bacterial communities 90 days before harvesting of tomato. The results showed that ASD treatment reduced R. solanacearum abundance in soil by 17.6% pre-planting and 18.7% 90 days before harvesting, but BV inoculation did not influence R. solanacearum abundance. ASD and ASD+BV treatments effectively reduced the occurrence of bacterial wilt, improved soil nutrient status and increased soil microbial activity 90 days before harvesting. Principal co-ordinate analysis showed that the soil bacterial community was significantly influenced by ASD treatment both pre-planting and 90 days before harvesting. Further investigation found that ASD contributed to the enrichment of beneficial flora (Bacillus and Streptomyces). Moreover, pH was an important environmental factor affecting the abundance of R. solanacearum in soil. Co-occurrence network analysis showed that ASD treatment significantly increased network connection of bacterial communities and the proportion of beneficial microorganisms (Proteobacteria and Firmicutes), leading to complex soil bacterial co-occurrence networks both at pre-planting and 90 days before harvesting. Collectively, these results indicate that ASD treatment, but not microbial inoculation can enhance tomato plant resistance to bacterial wilt by improving soil quality and modulating the soil bacterial community.

Effects of Biochar on Soil Inorganic Phosphorus Components, Available Phosphorus, Enzyme Activities Related to Phosphorus Cycle, Microbial Functional Genes, and Seedling Growth of Populus euphratica under Different Water Conditions

Cow dung is a kind of high quality and renewable biological resource. Biochar made from cow dung can be used as a soil amendment to improve soil nutrient status. The relationship between soil water and phosphorus is very close, and the water status determines the form, content, and availability of phosphorus. In order to investigate the effects of biochar on soil inorganic phosphorus components, available phosphorus, enzyme activities related to the phosphorus cycle, microbial functional genes, and seedling growth under different soil water conditions were investigated. Field experiments were carried out by setting different water conditions (30%, 60%, and 100%) and biochar addition (0 t hm−2, 2.63 t hm−2, 5.26 t hm−2, and 7.89 t hm−2). The results showed that applying biochar significantly increased the soil’s accessible phosphorus content and the phosphorus content in both the aboveground and subsurface parts of P. euphratica seedlings. This is mainly attributable to biochar’s direct and indirect effects on soil properties. Because biochar is naturally alkaline, it raises soil pH and reduces acid phosphatase activity in the soil around P. euphratica seedlings in the rhizosphere. Perhaps the alkaline phosphatase level first showed an upward trend due to the combined impacts of water and biochar, and then it started to decline when the biochar addition was increased. Soil phosphorus functional genes phoC, phoD, gcd, and pqqc had an increase in copy number with biochar addition but not without treatment. Indirectly, the biochar treatment increased the soil’s phosphorus availability by increasing the population of the phosphate-solubilizing bacteria Fusarium and Sphingomonas. Soil phosphorus availability is positively affected by biochar under various water conditions. This impact is due to chemical and microbiological mechanisms.

Agricultural management could reduce soil N2O emissions while increasing grain yields via enhancing soil moisture harvesting and improving soil nutrient status

Intercropping can improve system productivity, but the effect of intercropping integrated with conservation tillage practices on soil N2O emissions remains unclear at the present stage. A 4-yr field experiment was performed in northwest China to examine soil moisture harvesting, soil nutrient status, and soil N2O emissions of wheat-maize intercropping with stubble residues and films management. We found that intercropping increased crop yields and reduced soil N2O emissions over monocultures. Across the intercropping treatments, NTSMFI (no-tillage with mulching stubbles and re-using residual films) and NTSSFI (no-tillage with standing stubbles and re-using residual films) boosted grain-yields by 13.8–17.1 % and 12.9–15.4 % over CTFI (conventional tillage without returning stubbles and mulching new films). NTSMFI and NTSSFI reduced soil N2O emissions by 18.4–28.7 % and 15.5–24.9 % compared to CTFI, respectively. So, NTSMFI and NTSSFI obtained a higher soil N2O emission efficiency than CTFI. The greater effect on soil N2O emissions reduction was detected in NTSMFI, and decreased by 5.1–5.4 % over NTSSFI. The main reason for NTSMFI to improve grain-yields and reduce soil N2O emissions was to enhance soil moisture harvesting and optimize the soil nutrient status. Compared to CTFI, NTSMFI increased the ratio of transpiration to evaporation by 14.4–32.0 %, improved soil organic carbon and total nitrogen concentrations, and soil C:N ratio of 0 to 60 cm soil depth by 14.1 %, 7.1 %, and 6.5 %, respectively. Adopting an environmentally clean strategy exemplified by NTSMFI was recommended as an effective technique for increasing-yields and reducing soil N2O emissions in arid irrigated regions.

Enhancing Productivity of Rajma (Phaseolus vulgaris L.) by Managing Soil Acidity and Organic Nutrient Management under Arunachal Hill Conditions

A study was conducted at farmers’ field of Tirap District of Arunachal Pradesh to test the effect of organic sources of soil nutrient management with Lime for soil acidity management and for yield improvement of Rajma (Phaseolus vulgaris L.) variety Chitra. The experiment was conducted by following 3 treatments: T1: (Lime @ 350 kg/ ha+ FYM @ 4 t/ha + Neem cake @300 kg/ha+ vermicompost @ 4 t/ha + Azospirillum 10kg/ha, T2: FYM @ 4 t/ha + Neem cake @ 300 kg/ha + vermicompost @ 4 t/ha + Azospirillum 10 kg/ha. T3: (Farmers’ Practice) -FYM + N: P2O5: K2O: 40:20:15 kg/ha (imbalance doses of fertilizers) with 5 replications following randomized block design during 2021-22. From the results it is revealed that T1: (Lime @ 350 kg/ ha+ FYM @ 4 t/ha + Neem cake @300 kg/ha+ vermicompost @ 4 t/ha + Azospirillum 10kg/ha, had showed significantly higher seed yield (10.2 q/ha), gross return (Rs 1,53,000/), net return (Rs 106,824) and B:C ratio (2.31), followed by T2 (FYM @ 4 t/ha + Neem cake @ 300 kg/ha + vermicompost @ 4 t/ha + Azospirillum 10 kg/ha), seed yield 9.3 q yield, Rs. 1,39,500/ gross return, Rs 95,620 net return and 2.17 B:C ratio. While, lowest yield and B:C ratio was recorded (7.1 q/ha, B: C ratio 1.84) with T3 (Farmer’s practice). Moreover, improved soil nutrient status was achieved in T1 followed by T2 and T3.

Exclosure effects on soil physicochemical properties and woody species diversity in the south Rift valley basin of Ethiopia

Establishing exclosures has become common rehabilitation and restoration of degraded lands in Ethiopia. This study examined the effects of exclosure on identified soil physical and chemical properties, and woody diversity at the Wamole sub-watershed. Representative soil samples were taken from the open grazing land and eight-year-old exclosure. Six transects and 18 plots, with an area of 20 m × 20 m and containing nine from each open grazing ground and nine from the exclosure, were constructed alongside to sample the vegetation. From every plot, by ‘X’ design, composite soil samples were collected for investigation of total nitrogen (TN), available phosphorus, cation exchange capacity (CEC), soil pH and soil organic carbon content (SOC), and the bulk density (BD) of the soil, 18 undisturbed soil samples were taken from 0 to 20 cm deep. 34 and 28 woody species belonging to 25 and 20 families were registered between exclosure and adjacent open grazing land respectively. Significantly (P < 0.05) higher Index Shannon-Wiener (3.36) in the exclosure indicated better species diversity in the exclosure than in the open grazing land (3.13). Soil properties such as available phosphorus, pH, OC, TN, and CEC showed significant differences (p < 0.05) across different land uses. Exclosures facilitated to reclaim of degraded lands by re-establishing vegetation and improving soil nutrient status in a comparatively short period. It suggests that further research on socio-economic aspects of exclosures has to bring livelihood improvement in the locality to establish additional degraded open grazing lands in the research sub-watershed.

Differential effects of cow dung and its biochar on Populus euphratica soil phosphorus effectiveness, bacterial community diversity and functional genes for phosphorus conversion.

Continuous monoculture leading to soil nutrient depletion may cause a decline in plantation productivity. Cow dung is typically used as a cheap renewable resource to improve soil nutrient status. In this study, our purpose was to compare the effects of different cow dung return methods (direct return and carbonization return) on soil microbial communities and phosphorus availability in the root zone (rhizosphere soil and non-rhizosphere soil) of P.euphratica seedlings in forest gardens and to explore possible chemical and microbial mechanisms. Field experiments were conducted. Two-year-old P.euphratica seedlings were planted in the soil together with 7.5 t hm-2 of cow dung and biochar made from the same amount of cow dung. Our findings indicated that the available phosphorus content in soil subjected to biochar treatment was considerably greater than that directly treated with cow dung, leading to an increase in the phosphorus level of both aboveground and underground components of P.euphratica seedlings. The content of Olsen-P in rhizosphere and non-rhizosphere soil increased by 134% and 110%, respectively.This was primarily a result of the direct and indirect impact of biochar on soil characteristics. Biochar increased the biodiversity of rhizosphere and non-rhizosphere soil bacteria compared with the direct return of cow dung. The Shannon diversity index of carbonized cow manure returning to field is 1.11 times and 1.10 times of that of direct cow manure returning to field and control, and the Chao1 diversity index is 1.20 times and 1.15 times of that of direct cow manure returning to field and control.Compared to the direct addition of cow dung, the addition of biochar increased the copy number of the phosphorus functional genes phoC and pqqc in the rhizosphere soil. In the biochar treatment, the abundance of the phosphate-solubilizing bacteria Sphingomonas and Lactobacillus was significantly higher than that in the other treatments, it is relative abundance was 4.83% and 2.62%, respectively, which indirectly improved soil phosphorus availability. The results indicated that different cow dung return methods may exert different effects on phosphorus availability in rhizosphere and non-rhizosphere soils via chemical and microbial pathways. These findings indicated that, compared to the direct return of cow dung, biochar return may exert a more significant impact on the availability of phosphorus in both rhizosphere and non-rhizosphere soils, as well as on the growth of P.euphratica seedlings and the microbial community.

Effects of Combined Application of Biochar and Different Types of Nitrogen Fertilizers on Rapeseed Root Growth and Properties of Purple Soil in Southwest China

To demonstrate the effects of combined application of biochar and different types of nitrogen fertilizers on the growth of plant roots and on purple soil properties such as soil nutrients, soil carbon content and soil respiration, a 206-day greenhouse pot experiment with rapeseed was conducted. Three types of nitrogen fertilizer were used: urea (UR), controlled-release urea (RU), a mixture of 60% urea and 40% controlled-release urea (40% RU), and biochar was added at mass fractions of 0% (C0), 2% (C1) and 4% (C2), with a control treatment (CK) without nitrogen fertilizer and biochar. The results showed that biochar significantly improved soil nutrient status, with the best effect observed when 40%RU was co-applied with biochar. The addition of biochar significantly increased soil total organic carbon (TOC) and particulate organic carbon (POC). Soil respiration increased with increasing biochar application, and the combination of 2% biochar and 40% RU showed a reduction in carbon emissions compared to the UR and RU treatments. The number of rapeseed root tips (NT), forks (NF) and crossings (NC) increased significantly with the addition of biochar, and the combination of biochar and 40% RU was more beneficial for root growth and development than RU and UR. Considering the improvement in soil nutrition, increased soil organic carbon content, reduced carbon emissions, and enhanced rapeseed growth and development, the co-application of 2% biochar and 40% RU is recommended for large-scale application in rapeseed cultivation in the hilly purple soil of southwest China.

Remediation of heavy metal-contaminated mine soils using smoldering combustion technology

Self-sustaining smoldering is an advanced technology for remediating Cd- or Cr(VI)-contaminated soils, but the effectiveness of this emerging thermal treatment for multiple metal-polluted mine soils remains unclear. In this study, self-sustaining smoldering technology for remediating multiple heavy metal-contaminated mine soils was investigated. The results showed that smoldering treatment reduced the mobility and bioavailability of heavy metals and improved soil nutrient status, thus facilitating the growth of plants. Better (>70%) Cu, Pb, and Cd fixation rates were obtained after smoldering treatment of the contaminated soils, thus mitigating the toxicity of heavy metals, as evidenced by the 38.60%–82.55%, 28.13%–85.79%, and 45.55%–98.09% reductions in DTPA-Cu, Pb and Cd, respectively, compared with the untreated soils. Moreover, pH, organic matter, total N, P, K, and the available P and K in remediated soils were significantly improved. The ryegrass seeds did not germinate in the multiple metal-contaminated mine soils. Conversely, the germination rates of ryegrass seeds in the treated soils after 21 days of cultivation were 73.33%–95.00%. The mechanism analysis revealed that the solid products formed during smoldering improved the soil nutrient status rather than the mineralogy. Due to the carbon-neutral nature of biomass energy and the self-sustainability of smoldering, this study provides a low-cost, energy-efficient, and low-carbon footprint method for remediating metal-contaminated mine soils in reclamation practices.

EVALUATION OF DIFFERENT RATES OF COMPOST MINERAL FERTILIZER ON THE GROWTH AND YIELD OF TOMATO

Compost – mineral fertilizer has dual effects; improving soil nutrient status and organic matter content which results to increase in yield of cultivated crops. A field experiment was carried out at the Ambrose Alli University Teaching and Research Farm, Ekpoma, Edo State, Nigeria to evaluate the effect of different rates of compost-mineral fertilizer and compost on the growth and yield of tomato. The experimental design was a Randomized Complete Block Design (RCBD) with seven treatments replicated thrice. The treatments were; control, recommended 10 tonnes of compost, 1, 2, 4, 6 and 8 tonnes/hectare (t/ha) of compost-mineral fertilizer. The initial soil analysis showed low nutrients status and the application of fertilizer was necessary to boost its fertility. Parameters taken were; plant height, stem girth, number of branches, number of flowers at 50% flowering, number of fruits and fresh weight of fruits. From the results, the application of 4, 6 and 8t/ha compost-mineral fertilizer significantly (p&lt; 0.05) increased the growth and yield of tomato compared to other treatments. The yield of tomato obtained from the application of 4, 6 and 8 tonnes of compost- mineral fertilizer (252.50, 272.00 and 294.50 t / ha) were not significantly (p&lt; 0.05) different from each other but significantly (p&lt; 0.05) higher compared to other treatments. Therefore, the application of 6 t / ha of compost-mineral fertilizer can be adopted by farmers for tomato production in the study area.

Grain, Yield and Quality of Transplant Aman Rice and Soil Nutrients Status with Application of Fertilizers and Green Manures

A field experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka during 2014 on transplant aman rice var. BR11 (Mukta) under different levels of chemical fertilizers and green manures to evaluate its grain yield, grain quality and soil fertility status with incorporation of green manures. The experiment was carried out in a split- plot design with three replications. The level of fertilizers (0, 100, 75, 50% of recommended dose, RFD) was placed in main -plot and levels of green manures management (0, 5 and 10 t ha-1 each Mimosa invisa (Lajjaboti) and Sesbania spp. (Dhaincha) in sub-plot. Recommended dose of fertilizers of 83N, 21P, 37K, 11S and 1.5 Zn kg ha-1, were applied in the form of urea, triple super phosphate (TSP), muriate of potash (MoP), gypsum and zinc sulfate, respectively. Sixty-day old Mimosa invisa and Sesbania spp. were in - vitro incorporated before aman transplantation. Combined application of 75% RFD along with Mimosa invisa @ 10 t ha-1 was proved to be the best management in producing higher grain yield (7.25 t ha-1) and that was at par with treatment 50% RFD plus Mimosa invisa @ 10 t ha-1. Quality of grain was increased markedly in respect of amylose, carbohydrate, and protein as well. Furthermore, the treatment improved soil nutrient status in respect of organic matter, nitrogen, sulfur and Zn over no incorporations of green manures. So, addition of green manure like Mimosa invisa could cut fertilizer cost by 25-50%.&#x0D; Bangladesh Agron. J. 2022, 25(2): 67-72

Potential of Moisture Conservation Practices to Improve Soil Properties and Nutrient Status of Robusta Coffee Plant

Soil moisture conservation practices (SMCPs) have been adopted in Uganda to adapt to the effects of climate variability. However, limited information exists on how conservation measures influence the physico-chemical properties of soil and coffee leaf nutrient concentrations. Thus, we determined the effects of selected SMCPs on the soil physio-chemical properties and leaf nutrient concentrations in Robusta coffee in a randomized incomplete block design, replicated three times, in Kituza, Uganda. Soil samples were collected from 0 to 20 cm and 20 to 40 cm depths, and analyzed in the laboratory following standard procedures for selected physio-chemical properties. Coffee leaf samples were picked from each treatment (open sun coffee (COSS), coffee cover crop, Desmodium intortum (CCS), coffee mulch, Miscanthidium violoceum (CMS), and coffee A. coriaria (ACS)). Bulk density was significantly (p &lt; 0.001) the highest under ACS (1.61 gcm−3) and lowest under CCS (1.29 gcm−3), and it significantly (p &lt; 0.001) increased with depth. The soil organic matter was higher than the optimum range of 1–3% at the 0–20 cm depth across different SMCPs, but within the optimum range at the 20–40 cm depth. Leaf nitrogen was significantly the highest under ACS (3.19%) and lowest under COSS (2.30%). Overall, the findings suggest that SMCPs improve the soil physio-chemical attributes and leaf nutrients for sustainable coffee productivity. However, ACS improved the leaf plant nutrition better compared to other SMCPs.

EVALUATION OF DIFFERENT RATES OF COMPOST MINERAL FERTILIZER ON THE GROWTH AND YIELD OF TOMATO

Compost – mineral fertilizer has dual effects; improving soil nutrient status and organic matter content which results to increase in yield of cultivated crops. A field experiment was carried out at the Ambrose Alli University Teaching and Research Farm, Ekpoma, Edo State, Nigeria to evaluate the effect of different rates of compost-mineral fertilizer and compost on the growth and yield of tomato. The experimental design was a Randomized Complete Block Design (RCBD) with seven treatments replicated thrice. The treatments were; control, recommended 10 tonnes of compost, 1, 2, 4, 6 and 8 tonnes/hectare (t/ha) of compost-mineral fertilizer. The initial soil analysis showed low nutrients status and the application of fertilizer was necessary to boost its fertility. Parameters taken were; plant height, stem girth, number of branches, number of flowers at 50% flowering, number of fruits and fresh weight of fruits. From the results, the application of 4, 6 and 8t/ha compost-mineral fertilizer significantly (p&lt; 0.05) increased the growth and yield of tomato compared to other treatments. The yield of tomato obtained from the application of 4, 6 and 8 tonnes of compost- mineral fertilizer (252.50, 272.00 and 294.50 t / ha) were not significantly (p&lt; 0.05) different from each other but significantly (p&lt; 0.05) higher compared to other treatments. Therefore, the application of 6 t / ha of compost-mineral fertilizer can be adopted by farmers for tomato production in the study area.

An innovative approach to improve oil production and quality of mustard (Brassica juncea L.) with multi-nutrient-rich polyhalite

Polyhalite popularly known as POLY4 is a multi-nutrient fertiliser containing K, S, Mg, Ca, and micronutrients. POLY4 has a low carbon footprint, is certified for organic agriculture, and has the potential to improve crop productivity and quality attributes Indian mustard which often faces challenges due to imbalanced nutrition supplied in the current fertilisation schedule. The hypothesis of the study was that the multi-nutrient fartiliser POLY4 can ensure balanced nutrition for Indian mustard. Considering this, a field experiment was conducted during the winter seasons of 2017–18 and 2018–19 to evaluate the effect of POLY4 on Indian mustard (Brassica juncea L.) with respect to its yield, quality, and nutrient uptake. POLY4 along with conventional sources of nitrogen (N) and phosphorus (P) was compared to recommended fertilisation practices from conventional sources of N, P, K namely urea, di-ammonium phosphate (DAP), and muriate of potash (KCl). With the application of POLY4, seed yield was significantly improved by about 600 kg ha−1 compared to NP control (no application of K and S) across the two seasons. Compared to recommended practice of NPK, the yield was increased by about 450 kg ha−1 with the application of POLY4. Mustard seed oil and protein percent were also improved with the use of POLY4. POLY4 did not have any adverse effect on the content of anti-nutritional factors and improved the omega-3 fatty acid content of mustard oil. Higher uptakes of macro and micronutrients in the crop were also recorded with POLY4 along with an improved soil nutrient status. From the economic point of view, it was also observed that the application of POLY4 resulted in an increment of net returns of USD 45–60 comparing cultivating mustard with the conventional N, P, K, and S fertilizers only. Therefore, the use of POLY4 as a source of multi-nutrient for balanced nutrition helped to increase the efficiency of applied nutrients which ultimately improved the yield and quality of mustard. This study exhibits the pioneer findings of polyhalite (POLY4) based balanced nutrition in Indian mustard.

Soil Test Based Balanced Fertilization (10 Years) for Improving Soil Nutrient Status and Use Efficiency Under Pearl Millet-Wheat Cropping System

Soil Test Based Balanced Fertilization (10 Years) for Improving Soil Nutrient Status and Use Efficiency Under Pearl Millet-Wheat Cropping System

INFEKTIVITAS MIKORIZA TANAMAN KELAPA SAWIT (Elaeis guinennsis Jack.) YANG TERSERANG GANODERMA

Palm oil (Elaeis guineensis Jacq.) is an important plantation crop in Indonesia as a producer of vegetable oil and several other derivative products. Palm oil (CPO) production is 47.18 million tons and PKO 4.6 million tons (GAPKI 2019). One of the main obstacles in palm oil cultivation is the presence of biotic stress in the form of Stem Root Disease (BPB) caused by the fungus Ganoderma boninense Pat. is the most harmful disease. In several palm oil plantations in Indonesia, this disease has caused the death of up to 80% or more of the entire population of oil palm plantations. Several factors that influence the development of BPB disease in the field are plant age, soil type, nutrient status and replanting technique. The characteristics of Ganoderma include soil borne, necrotropic and have various means of self-defense, therefore, BPB disease control must be carried out in an integrated manner between the use of resistant palm oil plants, the use of superior biological control agents and technical culture measures. One of the prevention alternatives that can be done is by utilizing soil microbes that can be in symbiosis with palm oil roots, such as Arbuscular Mycorrhizal Fungi (AMF). Mycorrhizae play a role in improving soil health, are environmentally friendly and able to improve soil nutrient status and agricultural products. Therefore, it is necessary to conduct research on the infectivity of mycorrhizae on healthy plants and plants that are attacked by Ganoderma. Keywords : Ganoderma, Infectivity, Oil palm

Effects of organic amendment incorporation on maize (Zea mays L.) growth, yield and water-fertilizer productivity under arid conditions

Land degradation is one of the world’s most pressing environmental problems and a constraint to agricultural production. Application of diverse organic amendments provides a management strategy to compensate for soil organic carbon depletion and reduce land degradation. The objective of this study was to investigate the effects of different organic amendments on soil properties, crop growth and water-fertilizer productivity under arid conditions. Soil in a maize field located in the upper reaches of Yellow River was amended with sheep manure compost and maize stover respectively. Five different application rates (2, 4, 6, 8 and 10 t ha-1) were carried out for the compost, and maize stover (6 t ha-1) combined with two different decomposing agents were implemented. Main component of the decomposing agent was Bacillus subtilis and Trichoderma harzianum, respectively. Soil aggregation and physical-chemical properties were generally improved with the incorporation of compost and maize stover. The addition of compost and maize stover reduced the bulk density and increased the field capacity, soil organic matter, aggregate stability and the saturated hydraulic conductivity. The emergence rate and maize growth properties improved in the organic materials amended plots. However, soil properties and crop growth non-monotonically varied with application rate of compost. The addition of different decomposing agents in maize stover amended plots did not show significant impact on most soil properties, but improved soil nutrient status, crop growth and yield with different levels compared with maize stover alone. Comprehensive analysis of yield, crop water productivity and partial factor productivity for nitrogen, incorporation of compost at a rate of 5–6 t ha-1 or 6 t ha-1 maize stover combined with Bacillus subtilis was recommended as a proper strategy in loamy soil under arid conditions.

Effects of long-term different fertilization patterns on soil nutrients and microbial community structure of tomato in a solar greenhouse.

The phospholipid fatty acid (PLFA) technique was used to investigate the effects of fertilization on soil characteristics and microbial community of tomato in a solar greenhouse in Shouguang, Shandong Province, China, based on a long-term (12-year) fertilization experiment. The experiment involved a control (CK) and five fertilization treatments, namely, traditional nitrogen application (CN), traditional nitrogen application+straw return (CNS), optimized nitrogen application (SN), optimized nitrogen application+straw return (SNS), and organic manure nitrogen application+straw return (MNS). Results showed that the contents of soil organic matter and avai-lable P and K under all fertilization treatments were significantly higher than that of CK, but no significant difference among fertilization treatments. The traditional nitrogen application (i.e., CN and CNS) significantly decreased soil pH. The reduction of nitrogen fertilizer (i.e., SN, SNS and MNS) did not affect soil pH. Compared with CK, no straw treatment (i.e., CN and SN) and MNS did not affect the content of soil available N, but nitrogen combined with straw returned (i.e., CNS and SNS) significantly increased soil available N content. The optimized N with straw return (i.e., SNS) treatment resulted in the highest soil available N. Compared with CK and treatments without straw (i.e., CN, SN), treatments with straw (i.e., MNS, CNS and SNS) substantially changed soil microbial community structure and increased the biomass of soil bacteria, fungi, actinomycetes, mycorrhizal fungi, and the total amount of PLFA. SNS treatment had the highest soil microbial diversity, the highest biomass of soil bacteria, fungi, and actinomycetes, the highest total amount of PLFA, the highest ratios of fungi/bacteria and monounsaturated fatty acids/saturated fatty acids (MONO/SAT), the two indicators for soil ecosystem stability. Further, it had the lowest ratios of iso/anteiso fatty acids (i/a) and gram-positive/gram-negative bacteria (G+/G-), the indicators for nutritional stress. Redundancy and correlation analysis revealed that soil organic matter was the main factor affecting soil microbial community structure, with a significant positive correlation with actinomycetes and gram-positive bacteria. In conclusion, straw returning combined with optimized nitrogen application (i.e., SNS, 8 t·hm-2 of wheat straw with N fertilizer reduced by 58.3%) could improve soil nutrient status, soil microbial biomass, soil microbial community structure, and soil ecological environment. It would be an effective measure for reducing fertilizer application and improving efficiency.

Driving mechanisms of climate-plant-soil patterns on the structure and function of different grasslands along environmental gradients in Tibetan and Inner Mongolian Plateaus in China

Grassland plants contribute to carbon fixation through photosynthesis, which can in turn produce plant biomass. Previous studies have demonstrated that vegetation productivity is enhanced by improved soil nutrient status in humid environments and is influenced by climate in arid environments. However, the responses of biomass productivity to different patterns of climate-plant-soil in different natural grassland ecosystems have not been clearly and comprehensively analyzed. In this study, we systematically explore the functional patterns of different grasslands, as well as the underlying mechanisms in the response to key climatic, soil, and plant factors. The survey range covered broad environmental gradients from humid, semi-arid, to arid environments in Tibetan and Inner Mongolian Plateaus. We found that the above- and belowground biomass production gradually decreased from humid, semi-arid, to arid environments. Biomass production was sensitive to climatic factors in different environments. However, compared to soil and plant factors, climate was always the most important factor determining biomass production in all grassland types. Furthermore, biomass production was regulated mainly by climate and soil characteristics in humid environments, but by climate in arid environments. Specifically, the corresponding limiting factors of each factor largely dominated the effects of the corresponding factors on different grasslands. For instance, the climate dominated by temperature negatively influenced the soil nutrient availability and then influenced the aboveground biomass production in alpine humid grasslands. These findings enhance our understanding of the heterogeneity of mechanisms of different grasslands along broad environmental gradients, which are crucial for predicting the effects and consequences of environmental change on terrestrial ecosystem functioning.

STATUS HARA TANAH DAN PERTUMBUHAN PEPAYA CALIFORNIA (Carica papaya L.) TERHADAP MOL NASI BASI

Papaya is a tropical fruit that is easy to cultivate and is one of the fruits that is widely consumed by people in Indonesia. Papaya California is one of the papaya varieties that are favored by the public because it has a sweeter taste than other papaya varieties. In an effort to reduce the use of inorganic fertilizers, the researchers made MOL made from spoiled rice in the hope that it can be used as an alternative in the cultivation of Californian papaya. This study used a randomized block design, where the researchers wanted to see how the MOL response of stale rice to soil nutrient status and growth of California papaya plants. The MOL of spoiled rice consisted of 4 levels, namely: N0 = 0 ml/L (control), N1 = 50 ml/L, N2 = 100 ml/L and N3 = 150 ml/L. The data obtained were analyzed and further tested with the 5% BNT test. The results showed that giving MOL of stale rice with this concentration had no significant effect on all observation parameters and was not significant in improving soil nutrient status.